History and References

In practice, c-squares builds on an established nomenclature for 10x10° squares on the earth's surface (World Meteorological Organisation, or WMO squares - ref. 1) and subdivides these further (e.g. into 5 x 5°, 1 x 1°, 0.5 x 0.5°, 0.1 x 0.1°, and so on) by extending a notation previously utilised for searching the Australian "Blue Pages" Marine and Coastal Data Directory. Once the relevant c-squares code or codes are entered into a searchable document (e.g. a database field, metadata record, or HTML web page), a simple text search for any desired square code will establish whether or not the record/document matches the user's spatial search requirement, giving an unambiguous "hit" or "miss". The c-squares string (one or more codes, with a designated separator character) can also be sent across the web very simply from any remote application to a custom c-squares mapper maintained on the Data Centre's server at CSIRO Marine Research. This will superimpose the supplied c-square extents on one of a variety of user-selectable base maps, with accompanying text if so requested, and can be used to quickly and effectively indicate the dataset spatial extent or footprint.

C-squares has been developed at CSIRO Marine and Atmospheric Research in Australia, over the period 2001 to current, and was given its first "official" release at the 2002 EOGEO technical workshop in Ispra, Italy in May 2002 (ref. 2). A formal article describing the system was published in March 2003 (ref. 3).

C-squares News and Site Update History

December 2005

Revised version (v.1.1) of the c-squares specification posted.

November-December 2005

Three new installations of the c-squares mapper are now online: (1) OBIS Australia (http://www.obis.org.au/cgi-bin/cs_map.pl); (2) University of Kiel IfM-GEOMAR in Germany (http://filaman.uni-kiel.de/cgi-bin/cs_map.pl); and (3) Swedish Museum of Natural History (http://uinen.nrm.se/cgi-bin/cs_map.pl). The original URL for the mapper at http://www.marine.csiro.au/cgi-bin/cs_map.pl will remain available and will redirect transparently to the installation on obis.org.au.

A number of new mapper features have been added; these will be documented in a revised "about mapper" page shortly.

November 2005

The "AquaMaps" project from the University of Kiel goes live, presenting interactive predicted distribution maps for hundreds of marine species utilising the c-squares mapper (For an entry point, go to http://filaman.ifm-geomar.de/tools/AquaMaps/HCMapSpeciesList.php).

April 2005

Oracle PL/SQL source code for validating a given c-squares code and c-squares string posted on resources page.

May 2004

Updated and improved example applications page created for the c-squares website, including reference to all current known applications running c-squares, plus a prototype mapping page (including c-squares mappers in SVG and Flash) from the Data Centre at the Australian Antarctic Division.

May 2004

Two papers on c-squares - related systems accepted for presentation at EOGEO 2004 technical workshop, London, UK, June 2004. Abstracts available here and here.

September 2003-March 2004

Full c-squares spatial indexing incorporated into major upgrade of OBIS, the Ocean Biogeographic Information System, running at Rutgers University, NJ, USA; revised version released 23 March 2004 (approx. 1.6 million records, of 20,000 different marine species, indexed).

August-September 2003

Prototype c-squares spatial search facility created for CSIRO Marine and Atmospheric Research Remote Sensing facility's archive of NOAA AVHRR satellite data, based on a c-squares index of "footprints" of c.60,000 satellite passes. Powerpoint presentation describing the method used available here.

10 June 2003

C-squares "lat/long-to-c-square converter" upgraded with new options to handle lines and polygons crossing the international date line, and polygons surrounding either the north or south pole (e.g. as with polar satellite data).

13 June 2003

C-squares FAQ ("Frequently Asked Questions") page added to the website.

10 June 2003

C-squares "lat/long-to-c-square converter" upgraded with new options to handle lines and polygons crossing the international date line, and polygons surrounding either the north or south pole (e.g. as with polar satellite data).

7 April 2003

Release of an upgraded version of the c-squares mapper, including:

• ability to specify for the initial c-squares to be plotted in any of a range of colours
• ability to plot multiple strings (in multiple colours) on the same base map
• capability to return "active maps" (with "click-on-a-square" functionality), to enable live spatial queries back to the supplier's own database.

Also created: a new, web input form "c-squares active map tester" for demonstration and testing of the new c-squares mapper features.

Technical details, along with the link to "c-squares active map tester", are available here.

24 March 2003

"c-squares-discuss" listserver established for interested developers and/or implementers to exchange information or post enquiries relevant to c-squares. To join the list, send an email to

  c-squares-discuss-request@marine.csiro.au

with the word 'subscribe' in the BODY of the email (note, anything in the subject line is ignored).
Then, to post a message, send it to

  c-squares-discuss@marine.csiro.au (note, only persons currently subscribed to the list are able to send messages to this service).

Archives of this list are available at http://www.marine.csiro.au/dmr/listarchive/c-squares-discuss/.

20 March 2003

"Official" system description, entitled "C-Squares", a New Spatial Indexing System and its Applicability to the Description of Oceanographic Datasets, published in Oceanography vol. 16 no. 1, March 2003.    .pdf copies posted on c-squares website in high resolution (file size 8.5 Mb) and low resolution (file size 0.5 Mb) versions.

7 March 2003

OBIS (the Ocean Biogeographic Information System, USA), http://www.iobis.org/, opts to use c-squares as primary spatial index for all its species records (approx 1 million now, and expected to grow rapidly over the next few years), to be functional before system launch in October 2003.

February-March 2003

Work Commenced on implementing "click on a square" functionality for the c-squares mapper - for example output, see this link, scroll down to the bottom of the page and click on "CMAR catches map", then click on (or close to) a red square or two.

February 2003

On-line c-square lat/long converter extended with prototype code to handle:

• lines (start point, end point)
• polylines (multiple lines where end point of one is start point of the next), and
• filled polygons

January 2003

New, improved version of "get_csquare" implemented for use at CSIRO Marine and Atmospheric Research.

24 December 2002

Revised "Oceanography" paper on c-squares submitted for publication following reviewers' comments; accepted for publication, 28 December.

2 December 2002

C-squares concept presented at the NASA's GCMD (Global Change Master Directory) system developers offices in Lanham, Maryland.

2 December 2002

C-squares concept presented at the US FGDC (Federal Geographic Data Committee) headquarters in Reston, Virginia. See Announcement and Powerpoint presentation delivered, via the FGDC website. (Copy of the same presentation also posted on the c-squares website here).

November 2002

C-squares concept presented at the 2002 Colour of Ocean Data Conference in Brussels. Abstract and Poster presentation available via the csquares website.

October 2002

High-level (10 slide) C-squares overview Powerpoint presentation prepared.

October 2002

"Google" internet search is successfully indexing the c-square codes posted within "MarLIN" metadata records - for an example pre-configured search, click this link.

26 August 2002

Added c-squares codes as explicit spatial references in "MarLIN" HTML metadata pages - to discover whether these can be used as a searchable field with internet search engines.

July-August 2002

Drafts prepared of official "c-squares system description" paper and circulated for comment to interested parties; initial version submitted to "Oceanography" magazine for consideration, 29 August 2002; also incorporating diagrams of WMO Squares provided by Ruth Curry, Woods Hole Oceanographic Institution) from her documentation to "Hydrobase", and satellite imaging tracks by Mike Botts from the "Space-Time Toolkit".

30 May 2002

Phoebe Zhang's Java implementation of "get_csquare" (from OBIS Distributed Data Search) and Eli Agbayani's ColdFusion version (from FishBase searches) posted on the c-squares website.

13 May 2002

First public presentation given on c-squares, at the 2002 EOGEO Technical Workshop, Ispra, Italy. Abstract and Powerpoint presentation available, via the EOGEO website (visit this link for list of all EOGEO 2002 presentations). (NB, Powerpoint presentation also available via the c-squares website, here).

10 May 2002

Coloured A4 handout/flyer for c-squares produced, in advance of the 2002 EOGEO meeting.

23 April 2002

C-squares used for spatial indexing of 200,000 biological "catch" records at CSIRO Marine and Atmospheric Research; index accessible via "CAAB" taxon master list (mainly for internal users, however 2 external examples accessible via Sample c-squares-enabled metadata records page - look for "orange roughy" and "brownband seaperch").

22 April 2002

Support for a new element "legend" added to the c-squares mapper.

20 March 2002

Initial c-squares search interface added to CMAR's "MarLIN" metadata system, after encoding some 500 records with relevant c-squares codes.

18 March 2002

Sea-Surface-Temperature (SST) images sourced from CSIRO's Division of Atmospheric Research added to the c-squares mapper, as new options for base maps.

12 March 2002

FishBase (http://www.fishbase.org/), adds c-squares mapping functionality to its "Point Distribution" and "Biogeographic Modelling" pages for any species.

6 March 2002

Initial version of an online c-squares lat-long converter constructed, and added to the website.

12 February 2002

The c-squares mapper now includes support for "Pacific centred" maps, i.e., longitude can change from +180 to -180 in the middle of the map without incurring a problem.

30 January 2002

OBIS (the Ocean Biogeographic Information System, USA), http://www.iobis.org/, adds c-squares mapping functionality to its "Distributed Data Search" facility for any species.

24 January 2002

"Enlarge" facility added for maps produced by the c-squares mapper.

22 January 2002

"get_csquare" PL/SQL code posted on website (example code to convert lat/long pair to a c-square reference)

21 January 2002

Draft version 1 of the c-squares specification posted.

1-15 January 2002

First version of the c-squares mapper constructed (initially as replacement for the off-line "Xerox PARC Map Viewer", now discontinued).

January 2002

Example c-squares enabled metadata record (from CMAR "MarLIN" metadata directory) posted on website.

13 December 2001

C-squares website started at this address (http://www.marine.csiro.au/csquares/).

Acknowledgments

Topographic base maps currently available for the c-squares mapper have been adapted from those made available by the (U.S.) National Geophysical Data Center/NOAA GLOBE project, and are used by permission.

Sea surface temperature maps are courtesy of Martin Dix, CSIRO Marine and Atmospheric Research.

Initial version of the CMAR c-squares mapper constructed by
Miroslaw Ryba and Tony Rees, CSIRO Marine and Atmospheric Research Data Centre, January-March 2002. Upgraded version by Philip Bohm and Tony Rees, March-April 2003.

References cited

• (1) U.S. National Oceanographic Data Centre. 1998. World Ocean Database 1998: Documentation and Quality Control, Version 1.2. Appendix 10A: World Meteorological Organization (WMO) Squares for the Atlantic and Indian Oceans and Appendix 10B: World Meteorological Organization (WMO) Squares for the Pacific Ocean.
• (2) Rees, Tony. 2002. "C-squares" - a new metadata element for improved spatial querying and representation of spatial dataset coverage in metadata records (abstract and presentation slides). EOGEO 2002 Proceedings, Ispra, Italy, May 2002. World Wide Web publication, available via the EOGEO website at http://eogeo.org/ .
• (3) Rees, Tony. 2003. "C-Squares", a New Spatial Indexing System and its Applicability to the Description of Oceanographic Datasets. Oceanography 16 (1), pp. 11-19.    .pdf versions available - file size 8.5 Mb (with high resolution figures) and file size 0.5 Mb (with low resolution figures).